1. Field of the Invention
The present invention relates to a recording material containing a carbonaceous powder whose surface is modified with a fluorine gas. More specifically, it relates to an ink for a writing instrument such as a ball-point pen or a felt pen.
2. Description of the Related Art
As an ink for use in a writing instrument such as a ball-point pen or a felt pen, there has heretofore been known an aqueous ink which can be prepared by dissolving or dispersing a dye or a pigment as a colorant in an aqueous medium comprising water singly or a mixture of water and a water-soluble organic solvent.
However, the conventional aqueous ink containing the dye is poor in fastness properties such as light resistance and water resistance. On the other hand, in the conventional aqueous ink containing the dispersed pigment, the problem of the fastness properties can be solved to some extent, but the long-term dispersing stability of the pigment is poor, so that the writing instrument tends to clog with time. Alternatively, the viscosity of the ink increases, so that any lines cannot be written by the writing instrument any more irrespective of a line writing speed, and in other words, writing is inconveniently impossible.